Monthly Archives: February 2008

While this hasn’t been the snowiest or the coldest winter I can remember, it still looms pretty large in my mind. Certainly it’s been bad enough to keep me indoors most of the season.

Today would have been no exception but for the fact that we have clear skies for a change as well as the last lunar eclipse for North America for about three years. I would have felt guilty staying inside, but I wasn’t about to stray far from the house. The observatory is still surrounded by 20 to 30 centimetres of snow, so the driveway became my observing platform of choice. I set up a tripod and set my trusty Canon on it, along with a second-hand lens I’m trying out and hope to buy if my funds will stretch that far. It’s a Canon 70-200 f/2.8 L series lens, and has a good reputation. In experiments with it as a portrait lens it’s done very well, so I thought I would try it for astro-imaging. I’ve combined a number of the images into the single image below:

100 mm f/2.8 ISO 800 Canon 40D, all at 1/10 second except the first at 1/5 second. Regulus is included from the first image

Here is a single frame from the series I took, with Saturn on the left of the moon, Regulus above. This is at 100 mm, with the lens wide open – I probably should have stopped down to f/5.6 for better results, and of course, I should have shot at 200 mm.

f/2.8 1/10 second, 100 mm, ISO 800, Canon 40D

This is a crop from another full frame,

f/2.8 1/10 second, 100 mm, ISO 800, Canon 40Dand I’m not entirely happy with it – I suspect it’s out of focus, though when you consider this is roughly the equivalent of a 100 cm x 65 cm (40″ x 26″) print, perhaps not. If it is out of focus, I don’t think it’s the fault of the lens – not so far, anyway. It was -14°C outside. Cold enough that when I was out there I may not have paid enough attention to what was going on with the focus, and it’s very possible that in the course of setting everything up I failed to set the focus correctly, or that the focus shifted as the lens cooled down from room temperature to ambient. I certainly failed to set the zoom up right – it’s showing a focal length of 100 mm when I intended to set 200 mm, and I do have one frame showing 200 mm. Things were a little hectic when I set up – I managed to freeze the camera and had to pull the battery to bring it back to normal. Things got moved as I inserted the remote release (I really hate the N3 connector), so I don’t trust anything I did.

I enjoyed the eclipse, and I’ll try shooting the moon with this lens some other, warmer, time.